Surfacing torch with external powder feed



July 2, 1963 K. LAMB SURFACING TORCH WITH EXTERNAL POWDER FEED 2Sheets-Sheet 1 Filed D80. 2, 195.9

| INVENTOR.

ATTORNEYS July 2, 1963 K. LAMB SURFACING TORCH WITH EXTERNAL POWDER FEED2 Sheets-Sheet 2 Filed Dec. 2, 1959 INVENTOR. W.

ATTORNEYS United States Patent 3,096,199 SURFACING TORCH WITH EXTERNALPQWDER FEED Kenneth Lamb, Valencia, Pan, assignor to Coast Metals Inc.,Littie Ferry, N..l., a corporation of Delaware Filed Dec. 2, 1959, Ser.No. 856,839 12 Claims. (Cl, 117-46) This invention relates to torcheshaving means for sup plying powdered metal to a heated surface. Thetorch can be used for welding where metal is to be added to the weld, orit can be used for applying a metal surface, such as a surface of hardermetal, to a work piece. The invention relates also to improved methodsfor applying surfacing metal to a Work piece by means of a heatingtorch.

It is an object of this invention to provide an improved heating torch,preferably an oxyhydrocarbon fuel gas torch, with means for sprayingpowdered metal on the surface which is heated by the torch. Theimprovements are concerned principally with spraying large quantities ofpowdered metal while keeping to a minimum the amount of powder lost bybouncing from the work piece or by being blown away. There are two typesof powderfeed torches. The first type has the powder supplied to the gasstream before the gas passes through the torch tip and the powder is,therefore, discharged through the tip to the flame jets. The second typefeeds the powdered metal into the flame beyond the tip face and nopowder passes through the tip. Torches of the second type can operatewith greater powder flow and are more suitable for applying surfacingmaterial to a work piece. This invention relates to the second type oftorch, that is, to torches having external powder feed.

It is an object of the invention to provide an improved apparatus andmethod for applying the powdered metal by entraining it in the interiorof the flame system. To accomplish this result, the flame system of theinvention is formed with a U-shaped or channel-shaped cross section openat the top, and the powder feed is in position to supply powder throughthe open top of the channelshaped cross section. This permits the powderto reach the center of the flame system and to be entrained within theflame in contrast to torches of the prior art where powder dropped onthe periphery of a flame system and had many of its particles blown awayby the flame envelope gases before the powder penetrated far enough intothe flame system to be entrained thereby.

Other features of the invention relate to the control of the powder feedto the flame system. The powder nozzle is located far enough ahead ofthe torch and spaced from it to avoid damage to the nozzle by the heatof the flame; and the nozzle is far enough ahead of the tip face toprevent the powder from entering into eddy currents of the gas streamwhich turn back in the immediate vicinity of the tip face and whichdeposit metal on the tip face when powder falls into these eddycurrents. The positioning of the nozzle in this invention is related tothe channel-shaped cross section of the flame system because greaterlatitude in the location of the nozzle is made possible by the fact thatthere is an opening in the top of the flame system and into which thepowder can drop.

The invention has valve means for controlling the powder flow and amanually-operated actuator for the valve means with locking elements forholding the valve means open when desired and with adjusting means forobtaining a minimum opening of the valve means and a greater opening asdesired upon operation of the actuator.

Another object of the invention is to provide an improved powder holderon the torch. One feature of the powder holder construction is the lowangle at which it is mounted so as to obtain a more compact torch and abetter balance of the torch. The powder holder is pro vided with meansfor facilitating feed of the powder in spite of the low angle, suchmeans including a smooth slip plate on which the powder rests, and avibrator which can be operated by a conveniently located switch on thehandle of the torch.

Other objects, features and advantages of the invention will appear orbe pointed out as the description proceeds.

In the drawing, forming a part hereof, in which like referencecharacters indicate corresponding parts in all the views;

FIGURE 1 is a side elevation of a torch made in accordance with thisinvention;

FIGURE 2 is an enlarged view, mostly in section, of the torch shown inFIGURE 1;

FIGURE 3 is an enlarged front view of the torch shown in FIGURES l and2;

FIGURE 4 is a sectional view taken on the line 4-4 of FIGURE 2;

FIGURES 5, 6 and 7 are diagrammatic views showing the operation of thevalve means;

FIGURE 8 is a greatly enlarged, fragmentary, diagrammatic viewillustrating the eddy currents of the flame gases in the immediatevicinity of the tip face; and

FIGURE 9 is a detail view of the vibrator used on the torch shown in theother views.

FIGURE 1 shows a torch 11 having a body portion 12 and a pistol-griphandle 14. There is a tip 16 at the forward end of the body portion 12,and there is a bracket 18 connected to the top of the body portion 12for supporting a powder holder 20 and a nozzle 21.

In the construction illustrated, the holder 26 is a plastic jar with ascrew cover 24 which is removed when the powder holder is to berefilled. The bracket 18 has a trough-like portion 26 into which theholder 20 fits and to which it is connected by a bolt 28. This bolt ismerely representative of fastening means for attaching the powder holder20 to the trough-like portion 26 of the bracket 18.

The torch is made more compact and its balance is improved by locatingthe powder holder 26 with its longitudinal axis at an acute angle to thelength of the torch, that is, to the direction in which gas isdischarged from the tip 16. The nozzle 21 has its axis at a somewhatsteeper angle for promoting gravity flow of the powder.

Within the powder holder 20 there is a slip plate 30 shaped to fitagainst the inside surface of the powder holder 20 and made of metalwith a smooth surface over which the powder slides easily.

The slip plate 30 extends for most of the length of the powder holder inthe preferred construction of the invention and the bolt 28 is bonded tothe under side of the plate 30 so as not to leave any head which wouldbe an obstruction to the powder flow. With this slip plate 30 it ispractical to construct the powder holder 20 of light plastic material,and preferably transparent material so that the operator can observe thepowder and know when the supply is getting low.

In order further to facilitate the feeding of the powder by gravity, thetorch has a vibrator 32, best shown in FIGURES 3 and 9. This vibratorhas coils 34 and 35 which attract an armature 36 that carries onecontact of a switch 38. Power is supplied to the vibrator 32 through awire 4-0, the other side of the circuit being grounded on the torchbody.

The vibrator 32 operates in accordance with the usual doorbell or buzzerconstruction and it is wound for low voltage power so that it can beconnected with a battery. This makes the torch suitable for use in thefield where electric power is not available except from a portablesupply such as a battery.

The wire 40 leads to a switch 44 (FIGURE 2) located in the pistol-griphandle 14 with an operating button at a convenient position to be pushedby the thumb or a finger of an operators hand while gripping the handle14. On the other side of the switch 44 there is a wire .46 leading to areceptacle, 48 at the back of the torch body. One side of the receptacleis grounded on the torch body by another wire 49. The receptacle 48 hasopenings in the back of the torch for receiving prongs of a drop cordfitting which connects with a battery or other source of power.

Gas is supplied to the torch tip 16 through two tubes 54 and 55extending through the body portion of the torch. An end fitting 56 has abranch 58 for connection with "a hose to supply fuel gas to the tube 54.Another branch 59 of the fitting 56 is connected with a hose leading toan oxygen supply.

There are valves within the torch body for regulating the flow of gasthrough the tubes 54 and 55. These include a valve 64 commanding theflow of gas through the tube 54, and another valve. 65 for controllingthe flow of gas through the tube 55. The operating means for, the valve64 includes a knob 67 located on one side of the torch and the valve 65is operated by a knob 63 on the other side of the torch.

Powder is supplied from the powder holder20 to the nozzle 21 through aflexible tube 72 located in a passage in the bracket 18. This flexibletube 72 may be made of rubber or plastic, and the upper end of itextends through an opening in the bottom of the powder holder 26 andnear the lowest portion of the powder holder. The other end of the tube72 extends into the upper end of the nozzle 21. In order to cut ofi thepowder feed from the holder 29 to the nozzle 21, the flexible tube 72 ispinched and flattened to close it at a location between the powderholder and the nozzle. There is a push rod 74 with a rounded end whichcontacts with the flexible tube 72 to pinch the tube without abradingit. This push rod 74 slides in a sleeve 76. The sleeve 76 has adiagonally-cut end the lower portion of which is rounded off to contactwith the flexible tube 72 so that the tube can also be pinched by thesleeve 76. Thus, the open cross section of the flexible tube 72 may beclosed by the push rod 74, as shown in FIGURE 5, or by the sleeve 76, asshown in FIGURE 6. Normally, the push rod 74 and sleeve 76 are bothurged against the flexible tube 72 to pinch it closed.

The end of the push rod 74, remote from the flexible tube 72, slides ina bearing 78 which consists of a cylindrical opening through a back wallon the upper part of the torch body 12. There is a stop comprising acollar 80 rigidly connected to the push rod 74; and a spring .82 iscompressed between the collar 80 and the back wall of the torch body.This spring 82 urges the push rod 74 toward the flexible tube 72'andkeeps the flexible tube pinched to block powder flow except When thepush rod is pulled back or held back by means which will be described.

The push rod 74 and the flexible tube '72 which is pinched by the rod toreduce the open cross section of the tube, or to close it altogether,constitutes a valve means controlling the flow of powder from the holder20 to the nozzle 21, and for regulating the flow of powder by varyingthe extent to which the open cross section is closed by the push rod 74.The actuating mechanism for this powder feed valve means includes atrigger 86 extending below the torch body 12 in front of the pistolgriphandle 14. The trigger has a bifurcated upper end connected to the torchbody by a pivot pin 88. A trans verse bar 90 is brazed or otherwisesecured to thelower side of the sleeve 76, and this bar 90 engages arecess 92 (FIGURE 7) in the back of the trigger 86. When 'the trigger 86is pulled back (toward the right in FIG- URE 7), the bar 90 and thesleeve 76 are also pulled back to release the flexible tube 72 from thepressure of the sleeve 76. During this movement of the sleeve 76, thebar 90 has a slight rotary movement in the recess 92 pressure of theoperators finger against the trigger 86' permits the spring 82 to pushthe collar toward the left in FIGURE 7, and thus restore the push rod 74to its original position in which it closes the cross section of theflexible tube 72, as shown in FIGURE 5.

The sleeve 76 is urged against the flexible tube 72 by a spring (FIGURE2) stretched between a bar 101 bonded to the sleeve 76 some distanceahead of the bar 91' and an anchor location 163 on the bracket 18.

The sleeve 76 extends through an outer sleeve 106 which is free on thesleeve 76; but a set screw 110 threads through the side wall of theouter sleeve 106 and extends through an opening 112 (FIGURE 1) in a sidewall of the torch body. The head of the screw 110 is enlarged to providea knob for manually rotating the screw.

Since the opening 112 is at a fixed location on the torch body, thescrew 110 is free to rotate about its axis but cannot move lengthwise ofthe torch body. When the screw 110 is rotated to the right until itclamps against the sleeve 76 (FIGURE 7), the sleeve 76 is held againstlongitudinal movement. When the sleeve 76 is pulled back by the trigger86 to open the tube 72, and the screw 110 is clamped against the sleeve76, it becomes impossible for the sleeve 76 to return to its normalposition in which it pinches the flexible tube 72. This maintains thepush rod 74 in its retracted position because the collar 89 is againstthe end of the sleeve 76.

It will be apparent that the screw 110 can be clamped against the sleeve76 with the sleeve 76 in any position. Thus, the set screw 110 can beused to hold the sleeve 76 and push rod 74 in positions which onlypartially open the tube 72. i

The stop collar 80 can be held in various adjusted positions by a setscrew 116 threaded through a side wall of the torch body in position toclamp the push rod 74. This set screw can be clamped against the pushrod 74 when the push rod is fully retracted or when the push rod is atany intermediate position with the powder flow tube 72 open to anydesired degree.

If the trigger 86 is pulled back to open the powder sup ply tube 72 fora desired rate of powder flow, and the set screw 1 16 is then clampedagainst the push rod 74, the trigger can not be moved back any fartherto increase the powder flow. However, it the trigger is released, thesleeve 76 will move away from the collar 80 and return to its normalposition where itpinches the tube 72 and shuts 011 the powder flow. Assoon as the operator wishes to renew the powder flow, however, he pullsthe trigger 86 back until the tube 72 contacts with the collar 80 andthis results in the same opening as the last operation of the triggersince the collar 80 is held in its previous position by clamping of theset screw 116 against the push rod 74. Thus the collar 80 provides astop with which a portion of the valve means, specifically the tube 74,comes into contact to limit the movement of the valve means toward openposition.

Thus, the set screw 116 provides a means for setting the torch for aselected maximum powder flow without interfering with the operation ofthe trigger for stopping and starting the powder flow.

FIGURE 3 is a front view of the tip 16. A plurality of flame jetorifices 120 open through the face of the tip and they are located alonga curved line having the shape of a U. The flame jets which are formedby the gas streams from these orifices 120 from a continuous system offlame along the line of the U, but the flamesystem is open at the topbecause of the absence of any top orifices. Thus, the flame system fromthe orifices 120 has a channel cross section with the channel open atthe top.

The nozzle 21 is located above the open top of the flame system so thatpowder dropping by gravity falls through the open top of the flamesystem and into the interior or mid-portion of the flame system where itbecomes entrained in the flame jets by which it is carried to the workpiece, being strongly heated by the flames during its passage to thework piece. Although the direction of the powder flow is changedabruptly upon striking the flame jets, little or no powder is blown awaybecause of the side flames which deflect powder back to the center ofthe stream in the event of any spreading of the powder stream when itstrikes the bottom of the flame system. By the time the flames andpowder strike the work piece, the powder is traveling at high velocityand is well distributed in the flames.

FIGURE 8 shows one of the flame jets adjacent the face of the tip 16 andthe arrows representing the gas flow of the flame jet indicate thedirection of the flow. Because of the friction of the gas against thesides of the jet passage, and the sudden decrease in gas pressure as itemerges from the tip, there is some turbulence at the boundary layer ofthe gas jet, as indicated by the curved arrows in FIGURE 8. Powderfalling into a flame jet near the tip face, or powder particlesdeflected into these eddy currents indicated by the curved arrows, buildup on the face of the torch and eventually interfere with the flow ofgas through the jet orifices.

With this invention, the nozzle 21 is located far enough ahead of thetip 16 to drop the powder into the flame system beyond the region ofeddy currents.

Ordinarily, such spacing of the nozzle from the flame system places thenozzle in a position where the envelope gases have begun to expandsuificiently to strongly heat the nozzle and at times, overheat it. Toavoid overheating of the nozzle, this invention locates the nozzle highenough above the gas flames so as to be out of danger of over-heatingand damage by the flame system. This is practical, even though itpermits greater spreading of the falling powder stream, because of thefeature of this invention which provides an open slot at the top of theflame system for receiving the powder into the flame system and thusavoiding loss of substantial quantities of powder which are deflectedand blown away and lost when dropped on an ordinary flame system whichdoes not have the channel cross section of the present invention.

The preferred embodiment of the invention has been illustrated anddescribed, but changes and modifications can be made and some featurescan be used in different combinations without departing from theinvention as defined in the claims.

What is claimed is:

1. In a torch for applying a coating to a work piece surface, and inwhich the torch has a tip face through which a combustible gas mixtureis discharged in a highvelocity jet system and is burned in a flamesystem beyond the tip face but with eddy currents that flow outward fromthe jet system and turn back toward the tip face immediately adjacent tosaid tip face, and there is a powder holder for powdered coatingmaterial located at a higher level than the tip and with a dischargepassage through which powder from the holder flows by gravity into theflame system, at a location outside of the torch and in front of thetip, and there are bracket means connecting the nozzle and powder holderto the torch, the improvement which comprises means for preventingpowder from being carried by said eddy currents into contact with thetip face with resulting build-up of coating material on the tip face,said means including a discharge nozzle at the end of the passage andfacing in a direction to discharge the powder from the passage into thebuming flame system transversely of the direction of flow of 6 the gasof the flame system from the tip, and supporting means holding thedischarge nozzle above the flame system and out in front of the tip faceat a distance to discharge the powder into the flame system ahead of theeddy currents.

2. The torch described in claim 1, and in which there is a vibratorattached to the torch adjacent to the discharge end of the powder holderfor facilitating flow of powder from the holder and through the nozzle.

3. The torch described in claim 1, and in which there is a smooth platelocated inside the powder holder and on the inside bottom wall of thepowder holder for reducing friction of the powder on the inside of theholder.

4. The torch described in claim 1, and in which the bracket means has atrough-shaped top surface, and the holder is a cylindrical jar with aremovable cap at its upper end, a plate in the jar and shaped to fit theinside surface of the jar, and extending for most of the length of thejar, and a screw extending through the plate and through the side of thejar and into a threaded opening in the bracket for holding the jaragainst the troughshaped top surface of the bracket.

5. The torch described in claim 4, and in which the cylindrical jar ismade of transparent plastic and the plate in the jar is made of metalwith a smooth top surface for facilitating the sliding of the powdertoward the lower end of the jar.

6. A torch for applying surfacing material to a work piece including incombination a torch body through which gas flows, a tip at the dischargeend of the torch body, the tip having an upwardly extending face with aplurality of orifices opening therethrough and in directions havingsubstantially horizontal components for projecting of gas jets from theface of the tip to produce a flame system outside of and in front of theface of the tip, a discharge nozzle for powdered metal, the nozzle beinglocated out in front of the face of the tip and high enough above thelevel of the orifices to be out of the flames, said flame jet orificesincluding some that produce a floor of flame on which the powder dropsby gravity and including at least two other jet orifices located nearthe upper end of the tip face and higher than other jets between themand in position to project upper flame jets on opposite sides of apowder stream falling by gravity from the nozzle whereby said upperflame jets reduce transverse .spreading of the powder stream.

7. The torch for applying surfacing material as described in claim 6,and in which there is at least one jet orifice in the lower part of theface of the tip in position to project a low flame jet under the powderstream, the low flame jet and the side flame jets providing a dynamicchannel into which the powder falls and by which it is carried intocontact with the surface of the work piece.

8. The torch for applying hard surfacing material as described in claim7, and in which there are several jet orifices on each side of thepowder stream and several jet orifices in the lower part of the tipproviding a plurality of flame jets for each side and a plurality offlame jets for the bottom of the dynamic channel.

9. Apparatus for applying surfacing material to a work piece including atorch having a tip from which a flame jet system is projected againstthe work piece, means for adjusting the rate of flow of gas to the flamejet system, a powder holder at a higher level than the torch tip, anozzle with a discharge end outside the tip face and adjacent to theflame system and extending in a direction having a substantial verticalcomponent, a passage connecting the powder holder and the nozzle andthrough which powder flo-ws by gravity from the holder to the nozzle,valve means movable into different positions to obstruct totally orpartially the flow of powder through the passage, manually-actuatedmeans on the torch operably connected to the valve means for operatingsaid valve means, a stop with which a portion of the valve means comesinto contact to limit the movement of the valve means toward openposition, said stop 'being adjustable to change the maximum opening ofthe valve means, and said stop including manually-operated means outsideof the torch for adjusting the maximum opening of the valve means andthe resulting powder flow in accordance with adjustment of the rate offlow of gas to keep the powder flow Within the carrying capacity of theflame jet system.

10. The apparatus described in claim 9, and in which the valve meansinclude two elements that pinch the tube, one of the elements being asleeve movableaxially, to press the end of the sleeve against the sideof the tube to pinch said tube, and the other element being a rod thatslids in the sleeve to bring the end of the rod against the tube topinch said tube, the stop including a rearward'part of the rod, andthemanually operated means being movable into position to .lock the-rodin any set position and a trigger operably connected to the sleeve andconstituting-the manually actuated means for operating the valve means.

11. The method of applying surfacing material to a workpiece by meansof-a gas torch comprising projecting a plurality of jets of oxygen andfuel gas with the jets in contiguous relation to one another and indirections to form a channel of flaming gas ahead of the torch, burningthe gases while flowing in said channel to produce walls of flame alongthe sides of the channel and a sheet of flame forming a bottom of thechannel, directing the channel of flame against the surface to becoated, and discharging the surfacing material, in powdered form, from alocation above the flaming gas and downwardly in a direction transverseof the direction of flow of the flaming gas and between the sides of thechannel and onto 8, the bottom of said channel of. flaming gas,- thepowder being introduced into the channel of gas at a location outside ofand ahead of. the torch for entrapment within said flame system andprojection against the surface of the work piece. v I

12. The methodof, applying surfacing. material to a work piececomprising projecting a plurality of jets of oxygen and fuel gas withthe jets in contiguous relation to one another and in directions to forma channel of flaming gas, burning the gases while flowing in saidchannel to produce walls of flame along the sides of the channel and asheet of flame forming a bottom of. the-channel, directing thechannel'of flame from a torch horizontally against a surface to becoated, and droppingpowdered coating material into the flame system bygravity at a region spaced downstream from the torch face, powderedmaterial being dropped from a region above the flame system and thespacing of the powderstream from the torch face being greater than anyjet orifice tubulence around'the flames-where they issue from the torchface.

References Cited in the file of this patent- UNITED STATES PATENTSCanada Dec. 23, 1 958

1. IN A TOORCH FOR APPLYING A COATING TO A WORK PIECE SURFACE, AND INWHICH THE TORCH HAS A TIP FACE THROUGH WHICH A COMBUSTIBLE GAS MIXTUREIS DISCHARGED IN A HIGHVELOCITY JET SYSTEM AND IS BURNED IN A FLAMESYSTEM BEYOND THE TIP FACE BUT WITH EDDY CURRENTS THAT FLOW OUTWARD FROMTHE JET SYSTEM AND TURN BACK TOWARD THE TIP FACE IMMEDIATELY ADJACENT TOSAID TIP FACE, AND THERE IS A POWDER HOLDER FOR POWDERED COATINGMATERIAL LOCATED AT AA HIGHER LEVEL THAN THE TIP AND WITH A DISCHARGEPASSAGE THROUGH WHICH POWDER FROM THE HOLDER FLOWS BY GRAVITY INTO THEFLAME SYSTEM, AT A LOCATED OUTSIDE OF THE TORCH AND IN FRONT OF THE TIP,AND THERE ARE BRACKET MEANS CONNECTING THE NOZZLE AND POWDER HOLDER TOTHE TORCH, THE IMPROVEMENT WHICH COMPRISES MEANS FOR PREVENTING POWDERFROM BEING CARRIED BY SAID EDDY CURRENTS INTO CONTACT WITH THE TIP FACEWITH RESULTING BUILD-UP OF COATING MATERIAL ON THE TIP FACE, SAID MEANSINCLUDING A DISCHARGE NOZZLE AT THE END OF THE PASSAGE AND FACING IN ADIRECTION TO DISCHARGE THE POWDER FROM THE PASSAGE INTO THE BURNINGFLAME SYSTEM TRANSVERSELY OF THE DIRECTION OF FLOW OF THE GAS OF THEFLAME SYSTEM FROM THE TIP, AND SUPPORTING MEANS HOLDING THE DISCHARGENOZZLE ABOVE THE FLAME SYSTEM AND OUT IN FRONT OF THE TIP FACE AT ADISTANCE OF DISCHARGE THE POWDER INTO THE FLAME SYSTEM AHEAD OF THE EDDYCURRENTS.